Protractor.



G. B DANNENBERG.

PROTRACTOR.

APPLICATION FILED JUNE 13,1914.

l@l33,54 Patented Mar. 30, 1915.

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PROTRAGTOR.

APPLICATION FILED JUNE 13, 1914.

1,1 33,540. Patented Mar. 30, 1915.

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camas n. DANNENBERG, or WILMINGTON, DELAWARE.

' Pno'rmic'ron.

Specification of Letters Patent.

Patented Mar. 30, 1915.

Application led June 13, 1914. Serial No. 844,974.

To all whom it may concern Be it known that I, CHARLES B. DANNEN- BERG, a citizen of the United States, residing 'at Wilmingtomin the county of New Castle and State of Delaware, have invented cer tain new and useful Improvements in Protractors, of which the following is a specification, reference being had to the accompan ing drawings.

is'invention'relates to certain improvements in protractors; and the object of the invention is vto provide a novel and improved device of this general character whereby thel desired results may be attained with convenience and economy.

The invention consists in the details of construction and invthe combination and arrangement of they several parts of my improved protractor whereby certain important advatages are attained and the device is rendered slmpler, less expensive and otherwise more convenient and advantageous for use, all as will be hereinafter more fully set forth.

The novel features of the invention will be carefully defined in the appended claims. In order that. my invention may be the better understood, I will now proceed to describe the same with reference to the accompanying drawings, wherein- Figure 1 is a plan view of a protracto'r constructed in accordance with an embodi-` ment of my invention, certain of the lead linesbeing shown in fragment in order to avoid confusion; Fig. 2 is an edge view of the device as herein embodied; Fig. 3 is 'an enlarged view in plan of the index herein embodied; Fig. 4 is an enlarged view in plan of the slide scale; Fig. 5 is a view, partly in elevation and partly in section, of the assembled index and slide scale; Fig. 6 is a sectional view taken substantially on the line 6-6 of Fig. 5; Fig. 7 is a sectional view, on an enlar ed scale, taken substantially on the line 'Z-g of Fig. 3; Fig. 8 is a view in perspective of the connecting plate herein included; Fig. .9 is a fragmentary view of a truss structure, in the laying-out of which my improved device is adapted to be employed;-Fig. 10 is a somewhat diagrammatic view of my improved device, illustrating the use of the same; and Fig. 11 is a diagrammatic view illustrating a further' example of the usages of my invention.

As disclosed in the accompanying drawings, 1 denotes a body formed preferably of blocks is divided by the dam proof bristol board and having outl1ne thereon the field 2 of rectangular formatlon and, as herein embodied, the longitudinal dimension is twenty-four inches and the transverse dimension ltwelve inches. The field 1s dlvided by the longitudinal and transverse lines 3 and 4, respectively, into square inch blocks,'the opposlte extremities of such l1nes having positioned in proximity thereto the scale indications 5, the indica tions along the transverse sides of the field extendlng forwardly in 'sequence from the inner` longitudinal edge of the field while the lndlcations along the longitudinal edges of the lfield are arranged in sequence in oppos1te directions from the longitudinal center of the field. Each of the square inch perpendicularly red lines 6 into sixty-four parts and in order that the intersection of the'lines 3 and 4 may be readily discerned in order to expedite the reading of the indicator, I have such points of intersection emphaslzed by the eavy dots 7.

Disposed longitudinally of the field is a semi-circular rline 8 described around the longitudinal center of the inner edge of the field and of a twelve inch radius and radiating from the longitudinal center of the lower edge of the field from the line 8 to the adjacent edges ofthe field are the heavy lines 9, the outer extremities of which being spaced apart a distance of one inch. The radial line 9, terminating at the forward corners of the field, is extended inwardly, as indicated at 9a, to the longitudinal center of the inner ed e of the field. c

ivotally engaged with the,'member 1 at the longitudinal center of the lower edge of the field-is the index member 10 formed of' transparent material, preferably .celluloid and having cut in its under surface,l longitudinally thereof, at its transverse center the line 11 leading from the pivot hole 12 produced in the index to the apex of the pointed extremity 14. Also out in the underI surface of the index are the linear scale 'graduations 15, while on the upper surface of the index are cut the indications 16. The under surface of the index 10 is adapted to lie vflat upon the member 1,y and by having tudinal line 11 and the graduati ns 15 cut on the under surface thereof, it will be readily perceived thatthe index may coact with the field with absolute accuracy which would not be true-if such line and Agr'adua'tior'is were sol 'the longiscale moved across to represent anyedge dis- Therefore 4 Y ing cut on the produced upon the upper face of the index, for reasons which are believed to be clearl obvious to those skilled in the art to Whic my present invention appertains.

17 denotes a plate formed preferably of a white metal having its opposite margins flexed to afford the guides 18 whereby the same may be slidably engaged upon the index 10, and in the upper surface of said plate 17 is out the line 19 which is adapted to -be brought in alinement with the line 11, bereinbefore referred to. The remaining marginal portions of the plate, which is substantially square in plan, are exed in a direction opposite to the direction of the guides 18 and serve to afford guides 20 for the slide scale 21 also formed of a transparent material, such as Celluloid, and havtop face thereof the linear graduations 22. and the indications 23, and it is to be observed that the indications on opposite sides of the graduations are re-l versely directed. it is to be understood that the guides 18 and 20 are such as to maintain the slide scale 21 perpendicular to the index 10. To the opposite extremities of the slide scale 21 are aixed the transverse wear strips k241 which are adapted to contact with the member 1 and to ness of the index 10 in order that no inaccuracy of indication may result. ln order to prevent wear, the member 1 may be covered with a sheet -15 of transparent material, such as Celluloid.

While my improved protractor may be employed in connection with dierent characters of work, I have found it especially applicable in connection with iron structural work, and it reduces to a minimum the time required in laying-out the "work by the draftsman, as with my device the necesslty of making a large scale lay-out of the Joints is avoided as t-he necessary clearances may be readily and accurately plotted by my protractor .as herein set forth. An example of a lay-out is shown in Fig. 9 wherein it is required to compute the distances a and b in order that the diagonals and gusset plates may be detailed so that when assembled the diagonals will clear the bottom chords and the vertical post. With my improved device to determine the distances w and b,`first set the index member or dial scale to the required slope of the diagonals (see Fig. 10) and then move the slide scale 21 across the dial until the lower corner of the slide'scale represents `a corner of the diagonal, with such tances a, and b can then be read in full size. Itis obvious that the index member or dial scaley can be set at any bevel and the slide tance on the diagonal members. if thedrawing 1s out of scale, the dev1ce proves itself more valuable than before.

i ing sketches or, sketch do for several braces.. As is believed compensate for the thickcorner at the'clearance line,`rthe dis-v Amon center.` f

In Fig. 11 is set forth. a samdle of combinin other wor makin one to be self-evident, it is only necessary to set the dial scale or index member to any of the bevels given and where the dial scale or index member crosses the horizontal line 3% inches up from the bottom ready through the index member or dial scale the diagonal distances d, e, f and g, as is believed to be clearly apparent to those skilledin the art to which my present invention appertains.

While my invention may be employed for different other purposes, I wish cable in reducing slopes to a certain bevel per foot. If you had a right triangle, 6 feet base and 8 feet altitude, and wish to reduce the slope to so much per foot so that the templet maker might more readily lay-out his work on the bench, it is only necessary to plot the distances 6 feet 0E horizontal and the 8 feet vertical aboveit and swing the center line of the index line or dial scale over the point, the index member then pointing to the required bevel per foot.

From the foregoing description, it is thought to be obvious that an indicator constructed in accordance with my invention is of an extremely simple and comparatively inexpensive nature and is particularly. well adapted foruse by reason of the convenience and facility with which it may be assembled, and it will also be obvious that my invention is susceptible of some change and modication without material departure from the principles and spirit thereof and for this reason 1 do not wish to be understood as limiting myself 'to the precise arrangement and formation of theseveral parts herein shown in carrying out my invention in practice.

'1 claim:

1. A devi-ce of the character described comprising a member divided into a plurality of blocks, a transparent index pivotally engaged with the member midway of a margin thereof and provided withv graduations, and a transparent slide scale provided with aduations carried by the index and movable at right angles thereto.

' 2. A device of. the character described comprising a member divided into a plurality of blocks,' a transparent index pivotally engaged with the member midway of a margin thereof and provided withvgraduations, a transparent slide scale provided with graduations carried by the index and movable at right angles thereto, saidmember being providedwith `afplurallty,V of radial lines with thepivotall point ofthe index as their coma a 'device of r11-bianca? described comprising a member divlded into a` plurality of blocks,la transparent index pivotally iso with the member midway a margin thereof and provided with graduations, and a slide scale provided with graduations carried by u sj the index and movable at right angles thereto.

In, testimony whereof I hereunto aiiix my signature in the presence of two witnesses.

CHARLES B. DANN ENBERG.

Witnesses:

WM. L. TODD, JAS. L. TODD. 

